Internal combustion engine



- V. RAFATLOFF' I I v INTERNAL COMBUSTION ENGINE I Filed Feb. 4, 1935Patented Aug. 3, 1937 UNITED STATES INTERNAL COMBUSTION ENGINE ValerienBai'ailofl, Paris, France Application February 4, 1935, .Serlal No.4,818

' In France February 6, 1934 2 claims. ,The present invention has forits object a new method of supercharging 4-cycle internal combustionengines and is intended to improve the conditions of operation of thecompressor. The.

present invention enables the present method of supercharging aeroplane,automobile engines, etc. to be simplified and improved. Furthermore, itpermits introducing into the cylinder arm kind of fuels, even thosewhich do not mix with each other.

The compressors used hitherto for superchargingengines generally operatewith a very high output and. at a speed of rotation of about 30,000

revs. per minute. It is obvious that such conditions of operation areharmful to the safety of operation of the engine and it can beconsidered that an engine which is supercharged in this manner can onlybe used for exceptional performances, without it being possible to useit in current practice. i

The method of supercharging according to the invention enables, for agiven motor, and for a given compressor, the output and the speed ofrotation of the compressor to be reduced while still obtaininga. perfectsupercharging.

The method according to the invention is essentially characterized bythe fact that the fuel is fed to the engine in two diflerent operations.The first charge of fuel is sucked in, in the usual so manner, throughthe inlet valve placed in the cylinder head. It is known that in thismanner the co-efficient of filling. of the cylinder is always less thanone. The second charge oi. fuel is let into. the engine, according tothe invention, through holes drilled in the cylinder wall near the lowerdead center of the piston, which holes are uncovered by the piston atthe end of its downstroke. Said holes are placed in communicationthrough a suitable conduit, with a compressor 40 and an auxiliarycarburettor.

In this manner, when .the piston, after having sucked in the chargesupplied by the usual valve, reaches its lower dead centre, it uncoversthe holes provided in the cylinder wall, and the second charge isintroduced into the cylinder.- The inlet of said second charge willcontinue as long as the holes are not again closed by the piston at thebeginning of its upstroke.- It will readily be understood thattheco-eificient of filling is thus considerably increased. The operationof the engine during the other phases is. the same as that of ordinaryengines. At the end of the expansion stroke, the holes provided in thecylinder wall will be uncovered again by the piston and an additionalintroduction will occur 01' the mixture supplied by the compressor andthe auxiliary carburettor. By varying the shape of the cam and thediameter 0! the exhaust valve, any desired pressure can be obtainedwithin the cylinder when the piston un-. covers the ports and inparticular such pressure can be made. less than that created by thecompressor, so that the latter always delivers into thecylinder when itis placed in communication with same.

The gases thus introduced into the cylinder, owing to their nature beingdifferent from that oi'the burnt gases, will form above the piston acushion which will finally drive out the burnt gases during the exhauststroke of the piston. In this manner the scavenging of the inside 01'the cylinder and the evacuation of the burnt gases will be efiected inapcrfect manner. on the other hand, the temperature of the ga whichremain in the combustion chamber at the end of the exhaust stroke andwhich will consist of the above-mentioned cushion of gas, will be lessthan that of the usual burnt gases. Consequently the temperature of themixture, during its inlet and, consequently, during the compression, isreduced in the supercharged engine according to the invention." It willreadily be understood that with a the supercharging system according tothe invention, the compressor operates under much more favorableconditions than in the present supe'rcharging systems. In the presentsystems, the compressor supplies the supercompressed carblllant mixtureou h the inlet valve throughout the whole of the inlet stroke whichcorresponds substantiallyto an angle of rotation of the crank shaft of200 to 220 under a pressure of the order of two atmospherw. With thesystem according to the invention the compressor supplies thecombustible mixture to the cylinder only when the piston uncovers theabove-mentioned holes. This period or opening. taking into account theprogressiveneas of the opening and the closing of said holes by thepiston. only corresponds to an angle oirotation o! the crankshaft or 50to Taking into account, on the other hand, the diflerence or pressurewhich is considerable since, according to the invention, it sutfloes tocompress the; additional mixture to 1.2 'or 1.3 atmospheres, it willreadily be understood that the work of the compressor, according to theinvention, will be 8 to 10 times less great than the work of thecompressor in the present systems operating under the same conditions.

Thus the compressor can operate under absolutely normal conditions with4,000 to 6,000 revs. per minute, while ensuring all desired safety.

On the other hand, it is known that an engine cannot be supercharged,from the point of view of economy and thermal efllciency, without makinguse of supercompression. But the supercompression necessitates havingrecourse to antidetonating substances such as tetraethyl lead. Thepresence of such antidetonating substances has a harmful action on thevalve, conduits etc. The supercharging method according to the inventionenables such harmful antidetonators to be replaced by harmlessantidetonators which could not be used hitherto owing to the fact thatthey do not mix with gasolene. Thus for example, a solution of water inalcohol, the vapour of which can be compressed up to 13 atmospheres,does not mix with gasolene. On the other hand, its vapours can mixfreely with gasolene vapours. Thus if, in the method according to theinvention, a normal carburant mixture is supplied to the usual inletvalve and alcohol vapours through the holes drilled in the cylinderwall, a perfect antidetonating combustible mixture can be obtained. Ingeneral, any mixture possessing antidetonating properties can besupplied through the holes drilled in the cylinder wall and even purewater or H202 which forms a perfect antidetonator and which does notharmfully afl'ect the operation of the engine, while lowering thetemperature of same. Oxygen can also be supplied through the holes.According to the invention, the compressor can be eliminated and theholes provided in the cylinder wall can be put in communication with theatmosphere by a suitable conduit. The supercharging and scavenging arein that case ensured by the inertia eifect of the air or mixture passingthrough such conduit and which, when the holes are closed by the piston,produces in the conduit near the piston over-pressure causing a freshinrush of air or of mixture in the cylinder when communication with thecylinder is again established.

The invention will be better understood with the help of theaccompanying drawing in which I have shown by way of example threeembodiments of the invention.

In Fig. 1 is shown in vertical section an engine equipped according tothe invention.

In Fig. 2 a modified construction is shown in which the secondcarburettor is replaced by a simple jet placed in the inlet piping.

In Fig. 3 a third embodiment is shown in which the compressor iseliminated.

Referring first of all to Fig. 1, I is the cylinder, 2 the piston, l8its connecting rod, and I! the crank case of the engine. Theusual inletvalve is shown at 5, the exhaust valve at 6, and the exhaust pipe at 4.The usual carburettor is' shown at I! and is connected with the valve 5by a pipe 3. Towards the end of its downstroke, the piston 2 uncoversholes provided in the wall of the cylinder I and which communicatethrough a pipe 8 in which is placed a butterfly control valve 0, with acompressor l0 and an additional carburettor II.

In the example of Fig. 2, the carburettor II is replaced by a simple jetl4, communicating through a pipe II with a fuel tank It; a cock I!enables the supply of fuel to be controlled.

In the case of Fig. 3, the compressor I0 is eliminated, and theautomatic supercharging and the scavenging are ensured by the inertia ofthe moving fresh air or antidetonating gaseous mixture in the pipe 8which then places the ports 'I of the engine cylinder in communicationwith the outer atmosphere.

When the piston 2 at the end of its suction stroke uncovers the lowerports 1, the outer air or mixture, whichhas a pressure greater than thatof the cylinder I, enters the cylinder and produces the supercharging.When the piston '2 again covers up the ports 1, the current of air or ofmixture passing through the pipe 8 being then suddenly interrupted, anincrease of pressure due to the inertia of the gas occurs in the portionof the pipe 8 near the piston 2, and which, when the piston uncovers theports 1, towards the end of its next downstroke, causes a new inrush ofgas in the cylinder i, thereby facilitating the scavenging of the burntgases.

As in the engine having a compressor, by suitably calculating thediameter of the exhaust valve and the shape of its control mechanism,the pressure in the cylinder for the period in question, can bedetermined and obtained at less than atmospheric pressure.

I claim:

1. The process of operating a four-cycle internal combustion enginewhich comprises introducing a primary charge of fuel mixture into thecombustion chamber of a cylinder during at least the greater part of theintake stroke, introducing a supercharging charge into the combustionchamber near the end of the intake stroke, compressing the compositecharge, exploding the compressed charge, reducing the pressure in thecombustion chamber of the cylinder during the latter part of the powerstroke resulting from said explosion, and thereafter introducing fuelmixture into said combustion chamber adjacent the piston head when saidpiston head is adjacent the lower dead center position of the powerstroke to replace the products of combustion adjacent said piston headand form a covering cushion of fuel mixture above the piston head toassist in more effectively expelling products of combustion at the endof the exhaust stroke.

2. The process of operating a four-cycle internal combustion engine,which comprises introducing a primary charge of fuel mixture into thecombustion chamber of a cylinder adjacent the top of said cylinder,introducing a supercharging charge into the combustion .chamber adjacentthe top of the piston head when said piston head is adjacent the. lowerdead center position of the intake stroke, compressing the compositecharge, exploding the compressed charge, and thereafter introducing afuel mixture into said combustion chamber adjacent the piston head whensaid piston head is adjacent the lower dead center position of the powerstroke to replace the products of combustion adjacent said piston headand form a covering cushion of fuel mixture above the piston head toassist in more eifectively expelling products of combustion at the endof the exhaust stroke.

vAmtamN RAFAILOFF.

